Polymer compositions having adhesive properties

ABSTRACT

Polymer compositions with adhesive properties comprising:
     (1) at least one fluoropolymer (A) grafted by at least one compound (a) containing at least one functional group (f1) capable of conferring adhesion properties on said polymer;   (2) at least one polyolefin (B) grafted by at most 4% by weight, relative to the weight of polyolefin (B), of at least one compound (b) containing at least one functional group (f2) chosen from acid and anhydride groups, optionally completely or partially neutralized by at least one neutralizing agent; and   (3) at least one olefin copolymer (C), for which at least 5% by weight of the repeat units are derived from at least one functional monomer (f3) capable of reacting with the functional group (f1) contained in the compound (a).

The present invention relates to polymer compositions with adhesiveproperties. It also relates to a method for manufacturing thesecompositions. It additionally relates to multilayer structures for whichone of the layers is composed of the polymer composition with adhesiveproperties.

It is known that polyolefins, especially high-density polyethylene, areused for manufacturing pipes and tanks for the transport and storage ofliquid hydrocarbons, in particular oils and fuels. The chemicalresistance and the impermeability of these polymers with respect tothese hydrocarbons are not however always sufficient for all the usagesfor which they are intended. To overcome this drawback, a barrier layerof another polymer is interposed between the hydrocarbon to betransported or stored and the polyolefin. Polymers that are bothchemically resistant and impermeable frequently used for this purposeare fluoropolymers, in particular homopolymers and copolymers of vinyland vinylidene fluorides.

These fluoropolymers have in turn another drawback: they do not adherewell to polyolefins. Hence, compositions have been developed with a viewto improving the adhesion properties of the fluoropolymers.

Thus, document EP-A-0650987, the content of which is incorporated byreference in the present description, describes polymers with adhesiveproperties, the main fluorine-containing hydrocarbon-based chains ofwhich are grafted by compounds comprising reactive or polar functionalgroups that have adhesive properties. These functional groups may becarboxyl groups, carboxylic anhydride residues, epoxy groups, hydroxylgroups, isocyanate groups, ester groups, amide groups, amino groups andhydrolysable groups containing a silyl or cyano radical. These polymersdo not however adhere well enough to polyolefins.

Japanese Patent Application (Kokai) JP-10-202804, published on 4 Aug.1998 in the name of Sekisui Chem Co, discloses a composition thatenables a layer of polyethylene and a layer of polyvinylidene fluoride(PVDF) to adhere to one another. This composition comprises a blend of35 to 65 parts by weight of methyl methacrylate-grafted polyethylenewith 90 to 10 parts by weight of polymethyl methacrylate. Theproportions of each of the constituents of the blend must be carefullycontrolled or risk leading to the delamination of the PVDF layer.Moreover, this composition has an unpleasant odour.

The present invention aims to provide a composition, that makes itpossible to adhere a polyolefin to a fluoropolymer, which does not havethese drawbacks.

The present invention therefore mainly relates to polymer compositionswith adhesive properties comprising:

-   (1) at least one fluoropolymer (A) grafted by at least one    compound (a) containing at least one functional group (f1) capable    of conferring adhesion properties on said polymer;-   (2) at least one polyolefin (B) grafted by at most 4% by weight,    relative to the weight of polyolefin (B), of at least one    compound (b) containing at least one functional group (f2) chosen    from acid and anhydride groups, optionally completely or partially    neutralized by at least one neutralizing agent;-   (3) at least one olefin copolymer (C), for which at least 5% by    weight of the repeat units are derived from at least one functional    monomer (f3) capable of reacting with the functional group (f1)    contained in the compound (a).

The polymer compositions according to the invention comprise at leastone fluoropolymer (A). The term “fluoropolymer” is understood to mean apolymer for which more than 50% by weight of the repeat units arederived from at least one fluoromonomer. The fluoropolymer may be ahomopolymer; it may also be a copolymer formed by several fluoromonomerswith one another, or else a copolymer formed by one or morefluoromonomers with one or more non-fluorinated monomers. Thesecopolymers may, in particular, be random copolymers, block copolymers orgraft copolymers.

The term “fluoromonomer” is understood to mean any monomer thatcomprises at least one fluorine atom; it customarily comprises at leastone ethylenic unsaturation. As examples of fluoromonomers, mention maybe made of fluorinated vinyl monomers, fluorinated styrene monomers suchas 4-fluorostyrene, fluorinated (meth)acrylic monomers such astrifluoroethyl acrylate and fluorinated conjugated dienes such as2-fluorobutadiene. The fluoromonomer is preferably a fluorinated vinylmonomer. The expression “fluorinated vinyl monomer” is understood todenote the monoethylenically-unsaturated fluorinated monomers that arealiphatic and that have one or more chlorine atoms and optionally, inaddition, one or more chlorine atoms, as the only heteroatom(s). Asexamples of fluorinated vinyl monomers, mention may be made of vinylmonomers that are free of hydrogen atoms such as tetrafluoroethylene,hexafluoropropylene and chlorotrifluoroethylene, and partiallyhydrogenated fluorinated vinyl monomers such as vinyl fluoride,trifluoroethylene, 3,3,3-trifluoropropene and, with most particularmention, vinylidene fluoride.

The expression “non-fluorinated monomer” is understood to mean anymonomer that is free of fluorine atoms; it customarily comprises atleast one ethylenic unsaturation. Examples of non-fluorinated monomersare: α-monoolefins such as, for example, ethylene and propylene; styreneand non-fluorinated styrene derivatives non-fluorinated chloromonomerssuch as, for example, vinyl chloride and vinylidene chloride;non-fluorinated vinyl ethers; non-fluorinated vinyl esters such as, forexample, vinyl acetate; non-fluorinated (meth)acrylic esters, nitritesand amides such as acrylonitrile and acrylamide.

As examples of fluoropolymers, mention may especially be made of thehomopolymers of vinylidene fluoride, vinyl fluoride, trifluoroethyleneor chlorotrifluoroethylene, and the copolymers that these fluoromonomersform with one another or with at least one other fluoromonomer asdefined above (including a fluoromonomer that does not contain hydrogenatoms, such as tetrafluoroethylene or hexafluoropropylene). As examplesof such copolymers and terpolymers, mention may be made of thecopolymers and terpolymers of vinylidene fluoride and the copolymers andterpolymers of chlorotrifluoroethylene with at least one otherfluoromonomer as defined above (including a fluoromonomer that does notcontain hydrogen atoms, such as tetrafluoroethylene orhexafluoropropylene). Mention may also be made of the copolymers andterpolymers of at least one of the fluoromonomers mentioned above withat least one non-fluorinated monomer.

The fluoropolymer (A) present in the compositions according to theinvention is preferably chosen from vinylidene fluoride polymers.

For the purposes of the present invention, a vinylidene fluoride polymeris a fluoropolymer (i.e. a polymer for which more than 50% by weight ofthe repeat units are derived from at least one fluoromonomer),comprising repeat units derived from vinylidene fluoride.

As examples of vinylidene fluoride polymers, mention may especially bemade of homopolymers of vinylidene fluoride, and copolymers thereof withother ethylenically unsaturated monomers, whether they are fluorinated(examples of other ethylenically unsaturated fluoromonomers are vinylfluoride, trifluoroethylene, tetrafluoroethylene,chlorotrifluoroethylene and hexafluoropropylene) or non-fluorinated(examples of ethylenically unsaturated non-fluorinated monomers areα-monoolefins such as ethylene and propylene; styrene andnon-fluorinated styrene derivatives; non-fluorinated chloromonomers suchas vinyl chloride and vinylidene chloride; non-fluorinated vinyl ethers;non-fluorinated vinyl esters such as vinyl acetate; non-fluorinated(meth)acrylic esters, nitrites and amides such as acrylamide andacrylonitrile).

The vinylidene fluoride polymers preferably contain more than 50% byweight of repeat units derived from vinylidene fluoride.

Particularly preferred vinylidene fluoride polymers are vinylidenefluoride homopolymers and random copolymers of vinylidene fluoride thatcontain 10 to 20 % by weight of at least one fluorinated comonomerchosen from hexafluoropropylene and chlorotrifluoroethylene.

According to the invention, the fluoropolymer (A) is grafted by at leastone compound (a)—defined and described in detail later on—which containsat least one functional group (f1) capable of conferring adhesionproperties on said polymer.

The functional group (f1) may be any group having a reactivity or apolarity such that it enables the fluoropolymer to develop adhesionforces, even with respect to materials that it is not normally possibleto adhere to this polymer. The functional group (f1) is generally chosenfrom those bearing at least one reactive function that does not takepart in radical mechanisms. It is usually chosen from:

-   (f1.1) groups derived from carboxylic acids, also known more simply    hereinbelow as “acid groups”; the carboxylic acids from which these    groups originate may be monocarboxylic or dicarboxylic acids;-   (f1.2) groups derived from carboxylic anhydrides, resulting from the    condensation of two carboxylic acid groups in the same molecule,    also known more simply hereinbelow as “anhydride groups”; the    carboxylic anhydrides that bear these groups may themselves derive    from monocarboxylic or dicarboxylic acids;-   (f1.3) groups derived from carboxylic esters, also known more simply    hereinbelow as “ester groups”;-   (f1.4) groups derived from carboxylic amides, also known more simply    hereinbelow as “amide groups”;-   (f1.5) epoxy groups, derived from compounds containing a cyclic    ether function;-   (f1.6) hydroxylated groups derived from alcohols, also known more    simply hereinbelow as “alcohol groups”; the alcohols from which    these groups originate may be monoalcohols or polyols.-   (f1.7) carbonyl groups;-   (f1.8) hydrolysable groups containing a silyl group.

Among all these groups, epoxy groups (f1.5), alcohol groups (f1.6) andcarbonyl groups (f1.7) are preferred. More particularly, the epoxygroups and the alcohol groups derived form diols are preferred. Epoxygroups give the best results.

The functional group (f1) contained in the compound (a) grafted to thefluoropolymer (A) is preferably capable of reacting with the functionalgroup (f2) contained in the compound (b) grafted to the polyolefin (B).The epoxy groups (f1.5), the alcohol groups (f1.6) and the carbonylgroups (f1.7) are examples of functional groups (f1) capable of reactingwith the functional group (f2) contained in the compound (b).

As mentioned, the fluoropolymer (A) is grafted by at least one compound(a) containing at least one functional group (f1). According to theinvention, the functional group(s) (f1) contained in the compound(s) (a)may belong to the same family or to different families. Thus, it is inno way excluded to use both a first compound (a) containing an epoxygroup and a second compound (a) containing one or more alcohol groups;similarly, it is in no way excluded to use a compound (a) containingboth an ester group and another group, for example an epoxy or alcoholgroup.

In order to be able to be grafted to the fluoropolymer (A), the compound(a) customarily contains at least one group (g) that makes the graftingof said compound (a) to this polymer possible. This group (g) isgenerally chosen from:

-   -   saturated or unsaturated hydrocarbon-based groups, capable of        participating in radical mechanisms, such as additions or        associations of radicals;    -   amino or phenol groups capable of participating in reactions of        nucleophilic character;    -   groups capable of easily forming free radicals such as peroxy        and azo groups.

Preferably, the group (g) is chosen from organic groups having at leastone unsaturated carbon-carbon bond, from amino groups and from peroxygroups. Organic groups having at least one terminal α,β-unsaturatedcarbon-carbon bond, such as vinyl, allyl, acryloyloxyalkyl andmethacryloyloxyalkyl groups for example, are particularly preferred.Vinyl and allyl groups give the best results.

Examples of compounds (a) that contain at least one organic group havingat least one terminal α,β-unsaturated carbon-carbon bond as group (g)and at least one group chosen from acid and anhydride groups asfunctional group (f1) are unsaturated monocarboxylic or dicarboxylicacids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid,itaconic acid, crotonic acid, citraconic acid,bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylic acid, maleic anhydride,itaconic anhydride, crotonic anhydride and citraconic anhydride. Maleicanhydride is generally preferred, in particular for reasons ofaccessibility.

According to one variant of the invention, the acid group(s) and/or theanhydride group(s) that may be contained in the compound (a) arecompletely or partially neutralized by at least one neutralizing agent.The neutralizing agent may be a hydroxide (such as an alkali metalhydroxide, for example sodium hydroxide), an inorganic salt, an organicsalt, or else a mixture of an organic salt and an inorganic salt.

The inorganic salt is preferably a carbonate, a bicarbonate, a phosphateor a monohydrogenphosphate of an alkali metal. Sodium carbonate isparticularly preferred.

The organic salt is preferably a carboxylate or a monohydroxycarboxylateor polyhydroxycarboxylate of a metal, which may especially be an alkalimetal, an alkaline-earth metal, a metal from group IIIa of the PeriodicTable of the Elements or a transition metal. Particularly preferably,the organic salt is a carboxylate of a transition metal or amonohydroxycarboxylate or polyhydroxycarboxylate of an alkali metal.Most particularly preferably, the organic salt is chosen from sodiumlactate and zinc acetate.

The neutralizing agent is used in an amount preferably greater than 0.5molar equivalents relative to the number of acid and/or anhydride groups(f1) contained in the compound (a). Furthermore, the neutralizing agentis used in an amount preferably less than 3 mol. eq. relative to thenumber of these functional groups (f1).

Examples of compounds (a) that contain at least one organic group havingat least one terminal α,β-unsaturated carbon-carbon bond as group (g)and at least one ester group as functional group (f1) are vinyl acetate,vinyl propionate, monomethyl maleate, dimethyl maleate, methyl acrylate,ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate,amyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, methylmethacrylate, ethyl methacrylate, n-propyl methacrylate, n-butylmethacrylate, amyl methacrylate, hexyl methacrylate, 2-ethylhexylmethacrylate, diethyl fumarate, dimethyl itaconate and diethylcitraconate.

Examples of compounds (a) that contain at least one organic group havingat least one terminal α,β-unsaturated carbon-carbon bond as group (g)and at least one amide group as functional group (f1) are acrylamide andmethacrylamide.

An example of compound (a) that contains at least one organic grouphaving at least one terminal α,β-unsaturated carbon-carbon bond as group(g) and at least one epoxy group as functional group (f1) is allylglycidyl ether.

Examples of compounds (a) that contain at least one organic group havingat least one terminal α,β-unsaturated carbon-carbon bond as group (g),and at least one alcohol group as functional group (f1) are allylalcohol and 3-allyloxy-1,2-propanediol.

Examples of compounds (a) that contain at least one organic group havingat least one terminal α,β-unsaturated carbon-carbon bond as group (g)and at least one carbonyl group as functional group (f1) are organicheterocyclic compounds containing a vinyl or allyl group attached to theheteroatom and the heterocycle of which bears the carbonyl bond, such asN-vinylpyrrolidone and N-vinylcaprolactam.

Examples of compounds (a) that contain at least one organic group havingat least one terminal α,β-unsaturated carbon-carbon bond as group (g)and at least one hydrolysable group containing a silyl group asfunctional group (f1) are vinyltrimethoxysilane, vinyltriethoxysilane,vinyltriacetoxysilane, γ-methacryloxypropyltrimethoxysilane andvinyltris(β-methoxyethoxy)silane.

Examples of compounds (a) that contain at least one organic group havingat least one terminal α,β-unsaturated carbon-carbon bond as group (g),and at least two functional groups (f1) of different nature, are:glycidyl acrylate and methacrylate (an ester group and an epoxy group asfunctional groups (f1)); hydroxyethyl acrylate and methacrylate andhydroxypropyl acrylate and methacrylate (an ester group and an alcoholgroup as functional groups (f1)), N-methylolmethacrylamide (an alcoholgroup and an amide group as functional groups (f1)).

Among all the compounds (a), the compounds containing at least onefunctional group (f1) chosen from epoxy groups, alcohol groups andcarbonyl groups, more particularly from epoxy groups and alcohol groupsderived from diols, are preferred. The most particularly preferredcompounds (a) are allyl glycidyl ether, 3-allyloxy-1,2-propanediol,N-vinylpyrrolidone and N-vinylcaprolactam. The best results wereobtained with allyl glycidyl ether.

The grafting of the compound (a) to the fluoropolymer (A) may be carriedout by any method known for this purpose. Depending on the chemicalproperties and the physical state of the compound (a), this grafting maybe carried out in the solid state, in solution, in suspension, in anaqueous medium or within an organic solvent. This grafting may also becarried out by irradiation, for example by means of an electron beam orby gamma radiation.

The grafting of the compound (a) to the fluoropolymer (A) is moregenerally carried out on a molten blend of the compound and polymer. Itis possible to operate in batch mode, in kneaders, or continuously, inextruders.

The reaction of grafting the compound (a) to the fluoropolymer (A) isusually promoted and initiated by a radical generator, at least when thegroup (g) of the compound (a) is not itself a group capable of easilyforming free radicals, such as peroxy and azo groups. As a radicalgenerator, use is generally made of compounds having a decompositiontemperature between 120 and 350° C. and a half life, in this temperaturezone, of around one minute. The radical generator is preferably anorganic peroxide, and more particularly an alkyl or aryl peroxide. Amongthese, mention may be made of benzoyl peroxide, dichlorobenzoylperoxide, dicumyl peroxide, di(t-butyl) peroxide, t-butylcumyl peroxide,1,3-di(2-t-butylperoxyisopropyl)benzene,2,5-dimethyl-2,5-di(t-butylperoxy)hexane and2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne.2,5-dimethyl-2,5-di(t-butylperoxy)hexane and dicumyl peroxide areparticularly preferred.

When the grafting of the compound (a) to the fluoropolymer (A) iscarried out continuously in an extruder, the radical generator and thecompound (a) may be introduced in any manner so long as they areintroduced continuously over time and they are well dispersed in themolten material. The radical generator and the compound (a) may beintroduced by spraying, for example by means of a spray-type injector oran atomizer or by injection into the molten mass. The introduction ofthe radical generator and the compound (a) via a masterbatch with thepowdered fluoropolymer (A) or via a masterbatch with a filler can alsobe envisaged.

According to one particularly preferred embodiment, the compound (a) isintroduced before the radical generator.

The expression “reaction in molten mass” is understood to mean, for thepurposes of the present invention, any reaction in the substantialabsence of solvent or of diluent and at a temperature at least equal tothe melting point of the fluoropolymer (A).

The term “extruder” is understood to mean any continuous devicecomprising at least one feed zone and, at its outlet, a discharge zonepreceded by a compression zone, the latter forcing the molten mass topass through the discharge zone. The discharge zone may additionally befollowed by a granulating device or by a device that gives the extrudedmaterial its final shape. Advantageously, use is made of known extrudersbased on the work of a single screw or of two screws which, in thelatter case, may cooperate in a co-rotating or counter-rotating manner(same direction of rotation or opposite directions of rotation).

Preferably, the extruder used according to the present invention isarranged so that it successively comprises one feed zone, one materialmelting zone, one homogenization zone, one reaction zone, optionally onezone for introducing additives, and one compression-discharge zonepreceded by one degassing zone. Each of these zones has a very specificfunction and is at a very specific temperature.

The feed zone has the role of carrying out the feeding of thefluoropolymer (A). It is customarily at a temperature less than or equalto 50° C.

The material melting zone has the role of carrying out the melting ofthe material.

The homogenization zone has the role of homogenizing the moltenmaterial.

The reaction zone has the role of carrying out the reaction.

The temperature in the melting zone and in the zone for thehomogenization of the material is customarily greater than or equal tothe melting point of the fluoropolymer (A).

The temperature in the reaction zone is customarily greater than orequal to the temperature at which the half life of the radical generatoris less than the residence time of the material in this zone.

The zone for introducing additives has the role of carrying out theintroduction of additives when the latter are added into the extruder.The temperature of this zone is generally a function of the viscosity ofthe material and the nature of the additives added.

The compression-discharge zone has the role of compressing the materialand of carrying out the discharge of the latter. The temperature in thecompression-discharge zone is generally a function of the viscosity ofthe material to be discharged.

The compound (a) is preferably introduced into the extruder before thehomogenization zone.

The radical generator is preferably introduced into the reaction zone ofthe extruder.

Whichever grafting method is used, the amount of compound (a) grafted tothe fluoropolymer (A), expressed as amount of compound (a), isadvantageously greater than 0.01% by weight, preferably 0.05% by weightor, better still, 0.1% by weight, relative to the weight offluoropolymer (A). Moreover, this amount is advantageously less than orequal to 5.0% by weight, preferably 3.0% and better still 2.0% byweight. The metering is customarily carried out by a chemical route(titration).

The polymer compositions according to the invention comprise at leastone polyolefin (B). In the present description, the term “polyolefin” isunderstood to mean a polymer for which more than 50% by weight of therepeat units, preferably more than 70% by weight of the repeat units,most particularly more than 90% by weight of the repeat units, arederived from at least one linear olefin.

As examples of linear olefins, mention may be made of linearα-monoolefins containing 2 to 12 carbon atoms, such as ethylene,propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene,1-decene, 1-undecene and 1-dodecene.

The polyolefin (B) may be chosen, in particular, from homopolymers ofthe aforementioned olefins and from copolymers of these olefins, inparticular copolymers of propylene with one or more comonomers, and alsofrom blends of such polymers. The comonomers may be chosen, inparticular, from the linear olefins described above, from styrenemonomers such as styrene and α-methylstyrene and from alkadienes; thepolyolefin (B) is, however, preferably free of repeat units derived froman alkadiene. The weight content of units formed from comonomers in thepolyolefins is advantageously less than 30% and preferably less than 10%by weight.

The polyolefin (B) is preferably free of repeat units derived from afunctional monomer (f3), such as those contained in the olefin copolymer(C); when the polyolefin (B) nevertheless contains such repeat units,their amount usually represents at most 4% by weight, and often at most2% by weight, of all of the repeat units of the polyolefin (B).

The term “polyolefin” is understood to equally well mean the polymers asdescribed above, taken separately, and the blends thereof.

Excellent results are obtained using a polyolefin (B) chosen fromhomopolymers and copolymers derived from ethylene and propylene, mostparticularly crystalline polymers derived from propylene and copolymersof propylene containing less than 10% by weight and preferably less than5% by weight of ethylene.

According to the invention, the polyolefin (B) is grafted by at leastone compound (b) containing at least one functional group (f2) chosenfrom acid and anhydride groups. The functional group (f2) and thecompound (b) corresponding to it generally meet the same definitions andlimitations as those that are applied respectively to the groups (f1.1)and (f1.2) and to the compound (a) corresponding to them, mentionedabove.

The functional group (f2) is therefore contained in the compound (b),which is customarily chosen from unsaturated monocarboxylic ordicarboxylic acids, and anhydrides of unsaturated monocarboxylic ordicarboxylic acids, such as acrylic acid, methacrylic acid, maleic acid,fumaric acid, itaconic acid, crotonic acid, citraconic acid,bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylic acid, maleic anhydride,itaconic anhydride, crotonic anhydride and citraconic anhydride. Maleicanhydride is most particularly preferred.

According to a certain variant of the invention, the functional group(f2) contained in the compound (b) is not neutralized; the functionalgroup (f2) is then chosen from the acid and anhydride groups (as theyare). In particular for reasons of availability, it is often preferredto use, as polyolefin (B), a polyolefin according to the presentvariant.

According to another variant of the invention, the functional group (f2)contained in the compound (b) is completely or partially neutralized byat least one neutralizing agent.

The neutralizing agent may be a hydroxide (such as an alkali metalhydroxide, for example sodium hydroxide), an inorganic salt, an organicsalt, or else a mixture of an organic salt and an inorganic salt.

The inorganic salt is preferably a carbonate, a bicarbonate, a phosphateor a monohydrogenphosphate of an alkali metal. Sodium carbonate isparticularly preferred.

The organic salt is preferably a carboxylate or a monohydroxycarboxylateor polyhydroxycarboxylate of a metal, which may especially be an alkalimetal, an alkaline-earth metal, a metal from group IIIa of the PeriodicTable of the Elements or a transition metal. Particularly preferably,the organic salt is a carboxylate of a transition metal or amonohydroxycarboxylate or polyhydroxycarboxylate of an alkali metal.Most particularly preferably, the organic salt is chosen from sodiumlactate and zinc acetate.

The neutralizing agent is used in an amount preferably greater than 0.5molar equivalents relative to the number of acid and/or anhydride groupspresent in the compound (b). Furthermore, the neutralizing agent is usedin an amount preferably less than 3 mol. eq. relative to the number ofthese groups.

All the definitions, comments and limitations regarding the grafting ofthe compound (a) to the fluoropolymer (A) apply, mutatis mutandis, tothe grafting of the compound (b) to the polyolefin (B), it beingunderstood that it is advisable to carry out said grafting so that theamount of compound (b) grafted does not generally exceed 4% by weight,relative to the weight of the polyolefin (B). Preferably, the amount ofcompound (b) grafted is less than or equal to 3% by weight, relative tothe weight of the polyolefin (B), most particularly less than or equalto 2% by weight. Moreover, the amount of compound (b) grafted isgenerally greater than 0.01% by weight, relative to the weight of thepolyolefin (B), preferably greater than 0.03% by weight, or better still0.1% by weight.

The polymer compositions according to the invention comprise at leastone olefin copolymer (C). The olefin copolymer (C) is usually a polymerdifferent from the polyolefin (B).

In the present description, the expression “olefin copolymer” isunderstood to mean a copolymer (i.e. a polymer for which the repeatunits are derived from at least two different monomers) for which morethan 50% by weight of the repeat units are derived from at least onelinear olefin.

Preferably, the olefin copolymer (C) contains at least 60% by weight,more particularly at least 75% by weight, of repeat units derived fromat least one linear olefin. The linear olefin is generally chosen fromlinear α-monoolefins containing 2 to 12 carbon atoms, such as ethylene,propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene,1-decene, 1-undecene and 1-dodecene. Preferably, the linear olefin isethylene.

At least 5% by weight of the repeat units of the olefin copolymer (C)are derived from at least one functional monomer (f3) capable ofreacting with the functional group (f1) contained in the compound (a).Preferably, the olefin copolymer (C) contains at least 8% by weight,more particularly at least 10% by weight, of repeat units derived fromthe functional monomer (f3). The olefin copolymer (C) does not generallycontain more than 40% by weight, preferably not more than 25% by weight,of repeat units derived from the functional monomer (f3). The functionalmonomer (f3), although generally different from the compound (a) definedabove, may nevertheless belong to the same families as the latter, itbeing understood, however, that it must be copolymerizable with thelinear olefin from which the repeat units of the olefin copolymer (C)derive, on the one hand, and it must be capable of reacting with thegroup (f1) contained in the compound (a), on the other hand. Taking intoaccount these limitations, the functional monomer (f3) is preferablychosen from:

-   (f3.1) functional monomers that contain at least one organic group    having at least one terminal α,β-unsaturated carbon-carbon bond and    at least one acid group, for instance unsaturated monocarboxylic or    dicarboxylic acids, such as for example acrylic acid, methacrylic    acid, maleic acid, fumaric acid, itaconic acid, crotonic acid,    citraconic acid and bicyclo[2.2.1]hept-2-ene-5,6-dicarboxylic acid.    Among these functional monomers, acrylic and methacrylic acids are    particularly preferred.

The acid group(s) present in the functional monomers (f3.1) aresometimes not neutralized; the functional monomer (f3) is then chosenfrom functional monomers that contain at least one organic group havingat least one terminal αβ-unsaturated carbon-carbon bond and at least oneacid group (as it is).

However, it is preferred that the acid group(s) present in thefunctional monomers (f3.1) are completely or partially neutralized by atleast one neutralizing agent, in particular when the functional group(f2) contained in the compound (b) is not neutralized.

The neutralizing agent for the functional monomers (f3.1) may be ahydroxide, an inorganic salt, an organic salt, a mixture of two of thesecompounds or a mixture of all three.

The inorganic salt may be a carbonate, a bicarbonate, a phosphate or amonohydrogenphosphate of an alkali metal. Sodium carbonate is preferred.

The organic salt may be a carboxylate or a monohydroxycarboxylate orpolyhydroxycarboxylate of a metal, which may especially be an alkalimetal, an alkaline-earth metal, a metal from group IIIa of the PeriodicTable of the Elements or a transition metal. Preferably, the organicsalt is chosen from sodium lactate and zinc acetate.

The neutralizing agent for the functional monomers (f3.1) is preferablya hydroxide, particularly preferably an alkali metal hydroxide and mostparticularly preferably sodium hydroxide.

The neutralizing agent for the functional monomers (f3.1) is used in anamount preferably greater than 0.5 molar equivalents relative to thenumber of acid groups present in the functional monomers (f3.1).Furthermore, the neutralizing agent is used in an amount preferably lessthan 3 mol. eq. relative to the number of these groups:

-   (f3.2) functional monomers that contain at least one organic group    having at least one terminal α,β-unsaturated carbon-carbon bond and    at least one ester group such as, for example, vinyl acetate, vinyl    propionate, monomethyl maleate, dimethyl maleate, methyl acrylate,    ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl    acrylate, amyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate,    methyl methacrylate, ethyl methacrylate, n-propyl methacrylate,    n-butyl methacrylate, amyl methacrylate, hexyl methacrylate,    2-ethylhexyl methacrylate, diethyl fumarate, dimethyl itaconate and    diethyl citraconate; among the functional monomers (f3.2), methyl    acrylate and methacrylate are particularly preferred;-   (f3.3) functional monomers that contain at least one organic group    having at least one terminal α,β-unsaturated carbon-carbon bond and    at least one amide group such as, for example, acrylamide and    methacrylamide.

Other functional monomers, such as vinyl ethers, for instance ethylvinyl ether and butyl vinyl ether for example, or such as other amides,for instance N-methylmethacrylamide, N-alkylacrylamides andN-dialkylacrylamides for example, may also be copolymerized with thelinear olefin from which the repeat units of the olefin copolymer (C)derive.

The functional monomer (f3) from which the repeat units of the olefincopolymer (C) derive is preferably capable of reacting and/or developingionic interactions (for example, interactions between an oxygen atom andan atom of an alkali metal, such as sodium) and/or of forming hydrogenbridge bonds with the functional group (f2) contained in the compound(b) grafted to the polyolefin (B).

The functional monomer (f3) from which the repeat units of the olefincopolymer (C) derive is particularly preferably capable of reactingand/or developing ionic interactions with the functional group (f2)contained in the compound (b) grafted to the polyolefin (B).

The functional monomer (f3) from which the repeat units of the olefincopolymer (C) derive is most particularly preferably capable ofdeveloping ionic interactions with the functional group (f2) containedin the compound (b) grafted to the polyolefin (B).

The functional monomers (f3.1), completely or partially neutralized byat least one neutralizing agent, are examples of functional monomers(f3) capable of interacting ionically with the functional group (f2)contained in the compound (b) grafted to the polyolefin (B).

The olefin copolymer (C) may contain repeat units derived fromfunctional monomers (f3) belonging to at least two different families.Thus, the olefin copolymer (C) may contain repeat units derived from atleast two functional monomers (f3), at least one functional monomer (f3)being chosen from the functional monomers (f3.1), optionally completelyor partially neutralized by at least one neutralizing agent, and atleast one other functional monomer (f3) being chosen from the functionalmonomers (f3.2). These may then be, for example, mixtures of at leastone functional monomer chosen from acrylic acid, methacrylic acid,sodium acrylate and sodium methacrylate, with at least one functionalmonomer chosen from methyl, n-butyl and isobutyl acrylates andmethacrylates.

It is not excluded for the olefin copolymer (C) contained in thecompositions according to the invention to also be grafted by a compoundchosen from the families to which the compound (a) or the compounds (b),described above, belong. However, the olefin copolymer (C) is generallyfree of grafted compound chosen from the families to which the compounds(b), described above, belong, and, very often, the olefin copolymer (C)is free of any grafted compound.

As olefin copolymers (C), the copolymers for which from 95 to 85% byweight of the repeat units are derived from ethylene and for which from5 to 15% by weight of the repeat units are derived from methacrylicacid, the acid functions of which are completely or partiallyneutralized by the sodium ion, are most particularly preferred.

The respective proportions in which the fluoropolymer (A), in itsgrafted form, and the polyolefin (B), in its grafted form, are presentin the compositions according to the invention, may vary to a largeextent, especially as a function of the respective amounts of compound(a) and of compound (b) grafted to said fluoropolymer and saidpolyolefin. In general, these proportions are such that the weight ratioof the fluoropolymer (A) to the polyolefin (B) [(A)/(B)] is between 95/5and 5/95. Preferably, the ratio [(A)/(B)] is between 60/40 and 40/60.The best results were obtained when the ratio [(A)/(B)] is close to55/45.

Without the scope of the invention being in any way limited by thistheoretical explanation, the proprietor of the present applicationbelieves that the olefin copolymer (C) is, due to its chemical nature,capable of serving as some kind of “compatible interface” or “binder” tothe fluoropolymer (A) and to the polyolefin (B). Under these conditions,the amount of olefin copolymer (C) present in the polymer compositionsaccording to the invention may be significantly below those of thefluoropolymer (A) and polyolefin (B). In general, the olefin copolymer(C) is present in the polymer compositions according to the invention inan amount of 0.1 to 10% by weight relative to the total weight of thelatter compositions, preferably in an amount of 0.2 to 5% by weight,most particularly in an amount of 0.5 to 2.5% by weight.

In one particular embodiment of the present invention [embodiment (I)],to which preference is generally given, one portion of the amount offunctional monomer (f3) [from which the repeat units of the olefincopolymer (C) derive] has reacted with one portion of the amount of thefunctional group (f1) [contained in the compound (a) grafted to thefluoropolymer (A)], thus chemically bonding the olefin copolymer (C) tothe fluoropolymer (A). According to this embodiment (I), it is preferredthat one portion of the amount of functional monomer (f3) [from whichthe repeat units of the olefin copolymer (C) derive] has reacted and/ordeveloped ionic interactions (for example, interactions between anoxygen atom and an atom of an alkali metal, such as sodium) and/or hasformed hydrogen bridge bonds with the functional group (f2) [containedin the compound (b) grafted to the polyolefin (B)], thus bonding theolefin copolymer (C) to the polyolefin (B); particularly preferably, oneportion of the amount of functional monomer (f3) has reacted and/ordeveloped ionic interactions with one portion of the amount offunctional group (f2); most particularly preferably, one portion of theamount of functional monomer (f3) has developed ionic interactions withone portion of the amount of the functional group (f2). Still accordingto this embodiment (I), it is preferred that one portion of the amountof functional group (f2) [contained in the compound (b) grafted to thepolyolefin (B)] has reacted with one portion of the amount of functionalgroup (f1) [contained in the compound (a) grafted to the fluoropolymer(A)], thus chemically bonding the polyolefin (B) to the fluoropolymer(A). Finally, still according to this embodiment (I), it is preferredthat one portion of the amount of the functional group (f1) [containedin the compound (a) grafted to the fluoropolymer (A)] and one portion ofthe amount of the functional group (f2) [contained in the compound (b)grafted to the polyolefin (B)] remain in the unreacted state, and aretherefore generally capable of conferring adhesion propertiesrespectively on the fluoropolymer (A) and on the polyolefin (B);particularly preferably, one portion of the amount of the functionalgroup (f1), one portion of the amount of the functional group (f2) andone portion of the amount of the functional monomer (f3) [from which therepeat units of the olefin copolymer (C) derive] remain in the unreactedstate, and are therefore generally capable of conferring adhesionproperties respectively on the fluoropolymer (A), on the polyolefin (B)and on the olefin copolymer (C).

In another embodiment of the present invention [embodiment (II)], theentire amount of the functional group (f1) [contained in the compound(a) grafted to the fluoropolymer (A)], the entire amount of thefunctional group (f2) [contained in the compound (b) grafted to thepolyolefin (B)], and the entire amount of the functional monomer (f3)[from which the repeat units of the olefin copolymer (C) derive] are inthe unreacted state. The polymer compositions according to the latterembodiment of the present invention are advantageously used as precursorcompositions to the preparation of the compositions according toembodiment (I) as explained in detail above.

The polymer compositions according to the invention may also compriseone or more customary additives for thermoplastic polymers such as, forexample, acid scavengers, lubricants, organic or mineral colorants,nucleating agents, fillers, stabilizers and flame retardants.

The polymer compositions according to the invention may be prepared byany known method. Advantageously, a method will be chosen that ensuresan intimate mixing of their constituents (A), (B) and (C).

Another aspect of the invention therefore relates to a method formanufacturing the compositions as described above, according to whichthe fluoropolymer (A), the polyolefin (B) and the olefin copolymer (C)are mixed as a molten mass. In the method according to the presentinvention, it is moreover preferred to react the fluoropolymer (A), thepolyolefin (B) and the olefin copolymer (C) as a molten mass. Theexpression “to react the constituents (A), (B) and (C)” should beunderstood to mean that at least two of the constituents (A), (B) and(C) are reacted with one another.

Thus, for example, in the method according to the present invention, theconstituents (A), (B) and (C) may first be dry pre-mixed, in therequired proportions, in any device suitable for this purpose, such as adrum mixer. The dry premix thus obtained is then melted either in batchmode, in batch devices such as kneaders, or in continuous devices suchas the extruders described above with respect to the grafting of thecompound (a) to the fluoropolymer (A). The premix intended to be meltedcan also be produced by the masterbatch technique. It is also possibleto feed the kneaders or the extruders with the constituents (A), (B) and(C) metered separately, without dry pre-mixing. Once the constituents(A), (B) and (C) are melted, the mixing of these constituents is carriedout or continued in any device suitable for this purpose.Advantageously, to do this, use is made of the same batch devices(kneaders, for example) or continuous devices (extruders, for example)as those previously used for the melting operation. Finally, whilecontinuing the melt-blending of the constituents (A), (B) and (C) orafter having finished the latter, the constituents (A), (B) and (C) arepreferably reacted as a molten mass in these same devices.

A person skilled in the art may easily determine the general operatingconditions of the mixing, melting and reaction devices by means of a fewprior routine trials. In the case of extruders, in particular, thetemperatures of the melting, homogenization and reaction zones aregenerally controlled between 140 and 270° C., preferably between 170 and240° C.; the pressure in the die is generally less than 200 bar,preferably 100 bar, and more preferably still 50 bar; the rotationalspeed of the screw or screws is generally between 50 and 2000 rpm,preferably between 200 and 1000 rpm.

Good use may be made of the adhesive properties of the compositionsaccording to the invention for producing multilayer structures, whichconstitute another subject of the present invention. These aremultilayer structures for which one of the layers is composed of thepolymer composition with adhesive properties. These structures containat least one other layer which may be composed of various, bothinorganic and organic, materials. As inorganic materials that may beincorporated into the composition of this other layer, mention may bemade of metals and metal alloys, such as aluminium and steel, forexample. As organic materials that may be incorporated into thecomposition of this other layer, mention may be made of thermoplasticpolymers. Examples of thermoplastic polymers that may be incorporatedinto the composition of this other layer are polymers containingfluorine that belong to the family of fluoropolymers (A) and polymerscontaining olefins of the same nature as that (those) present in theolefin polymer (B).

Good use may be made of the adhesive properties of the compositionsaccording to the invention for producing multilayer structures, whichconstitute another subject of the present invention. These aremultilayer structures for which one of the ladders is composed of thepolymer composition with adhesive properties. These structures containat least one other layer which may be composed of various, bothinorganic and organic, materials. As inorganic materials that may beincorporated into the composition of this other layer, mention may bemade of metals and metal alloys, such as aluminium and steel forexample. As organic materials that may be incorporated into thecomposition of this other layer, mention may be made of thermoplasticpolymers. Examples of thermoplastic polymers that may be incorporatedinto the composition of this other layer are the fluoropolymerscorresponding to the definition of the fluoropolymer (A) and thepolyolefins corresponding to the definition of the polyolefin (B), apartfrom when the polymers in question are not usually grafted.

Particular multilayer structures according to this aspect of the presentinvention are three-layer structures having an X/Y/Z configuration, forwhich the central layer Y is composed of the polymer composition withadhesive properties according to the invention and for which the layersX and Z are composed of a thermoplastic polymer, as defined above.Preferred multilayer structures are three-layer structures having anX/Y/Z configuration, for which the central layer Y is composed of thepolymer composition with adhesive properties according to the invention,the layer X is composed of a polymer (usually ungrafted) based onolefin(s) of the same nature as that (those) present in the polyolefin(B) and the layer Z is composed of a polymer (usually ungrafted) basedon fluoromonomer(s) of the same nature as that (those) present in thefluoropolymer (A).

These multilayer structures may be produced according to any processthat is known for this purpose and is compatible With the nature of theconstituent material of each layer. The assembling of the layers may becarried out, for example, by bonding or by hot press moulding of theconstituent layers to one another, by coating of a solid layer with apowder or a solution of the constituent material of the other layer(s);or else, in particular in the case where the constituent materials ofthe layers are thermoplastics, by coextrusion, by coextrusion-blowmoulding, by coinjection moulding and by coinjection moulding-moulding.

Coextrusion is particularly suitable for the production of multilayerstructures having an X/Y/Z configuration, for which the central layer Yis composed of the polymer composition with adhesive propertiesaccording to the invention, the layer X is composed of a polyolefin(usually ungrafted) of the same nature as that (those) present in thepolyolefin (B), in particular a homopolymer or copolymer derived fromethylene and/or propylene, and the layer Z is composed of afluoropolymer (usually ungrafted) of the same nature as that (those)present in the fluoropolymer (A), in particular a homopolymer orcopolymer derived from vinylidene fluoride. This coextrusion may becarried out, for example, in three extruders, preferably threesingle-screw extruders, feeding a sheet die via a feed-block orpreferably feeding three-layer tubular dies.

The multilayer structures thus produced may be manufactured in the finalform of sheets and films.

The multilayer structures thus produced may also be manufactured in thefinal form of hollow bodies, in particular tanks, bottles, containers,tubes and pipes. The layer X then preferably constitutes the outer(convex) layer of the hollow bodies, whereas the layer Z thenconstitutes the inner (concave) layer of the hollow bodies. The hollowbodies, in particular the tubes, conduits and tanks, are advantageouslyused for the transport and/or storage of liquid hydrocarbons, inparticular oils and fuels.

The following examples are intended to illustrate the invention withouthowever limiting the scope thereof.

EXAMPLE 1

In a Brabender Plasticorder PL 2000 kneader rotating at 50 rpm, apolymer composition was prepared by mixing together, at a temperature of190° C.:

-   (A) a random copolymer containing 85% by weight of vinylidene    fluoride and 15% by weight of hexafluoropropylene, for which the    melt flow index, MFI_(2.16kg/230°C.) (ASTM 1238 standard) was 8 g/10    min and which was grafted by molecules of allyl glycidyl ether (this    grafted copolymer was obtained by using, in a Clextral model BC 21    co-rotating twin-screw extruder, the feed zone of which was heated    at 170° C. and the extrusion die at 220° C., 15 g of allyl glycidyl    ether and 4 g of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (DHBP)    as radical generator, per kg of extruded copolymer);-   (B) a random copolymer containing 96% by weight of propylene and 4%    by weight of ethylene, which was grafted, conventionally in an    extruder, by maleic anhydride in the presence of DHBP as radical    generator, and the grafted anhydride groups of which were then    neutralized by a mixture of sodium lactate and carbonate to convert    it to an ionomer, of which the melt flow index, MFI_(2.16kg/230°C.)    (ASTM 1238 standard) was 2.3 g/10 min;-   (C) a product sold under the name SURLYN® 1802 by Du Pont which is a    copolymer containing around 90% by weight of ethylene and around 10%    by weight of methacrylic acid, the carboxylic groups of which were    completely or partially neutralized in the form of sodium ions and    of which the melt flow index. MFI_(2.16kg/230°C.) (ASTM 1238    standard) was 4.13 g/10 min.

The constituent (A) represented 54.5% by weight of the blend, theconstituent (B) 44.5% by weight and the constituent (C) 1% by weight.

A three-layer film was then prepared by coextrusion, of which theconstituent of the central layer was the polymer composition preparedfrom the above blend. The constituents of the outer layers wererespectively:

-   -   for the lower layer, the fluoropolymer mentioned in (A) above,        but not grafted;    -   for the upper layer, a random propylene/ethylene copolymer sold        under the name ELTEX® P KS 409 by Ineos (melt flow index,        MFI_(2.16kg/230°C.) (ASTM 1238 standard): 5 g/10 min).

The operating conditions of the coextrusion are mentioned in Table 1below.

TABLE 1 Single-screw extruder 1 Extrusion of the lower layer (screwdiameter: 20 mm) (average thickness: 70 μm) Barrel temperature (° C.)(*) 175-210-210 Pressure (bar) 88.4 Speed (rpm) 30 Single-screw extruder2 Extrusion of the central layer (screw diameter: 20 mm) (averagethickness: 35 μm) Barrel temperature (° C.) (*) 210-230-240 Pressure(bar) 48 Material temperature 208 Speed (rpm) 30 Single-screw extruder 3Extrusion of the lower layer (screw diameter: 20 mm) (average thickness:200 μm) Barrel temperature (° C.) (*) 210-210-210-220-220 Pressure (bar)72 Speed (rpm) 25 (*) from upstream to downstream of the extruder.

On exiting the extruders, the three extruded layers were taken up by athree-roll polishing stack brought to a temperature of 70° C. The filmobtained could not be delaminated into its constituent layers, whichattests to the adhesive properties of the central layer.

EXAMPLE 2

Example 1 was reproduced in every respect except that the randomvinylidene fluoride/hexafluoropropylene copolymer of constituent (A) ofthe blend was grafted with 10 g/kg of 3-allyloxy-1,2-propanediol. Theoperating conditions of the coextrusion are mentioned in Table 2 below.

TABLE 2 Single-screw extruder 1 Extrusion of the lower layer (screwdiameter: 20 mm) (average thickness: 70 μm) Barrel temperature (° C.)(*) 175-210-210 Pressure (bar) 63.1 Speed (rpm) 20 Single-screw extruder2 Extrusion of the central layer (screw diameter: 20 mm) (averagethickness: 35 μm) Barrel temperature (° C.) (*) 210-230-240 Pressure(bar) 35 Material temperature 206 Speed (rpm) 20 Single-screw extruder 3Extrusion of the lower layer (screw diameter: 20 mm) (average thickness:200 μm) Barrel temperature (° C.) (*) 210-210-210-220-220 Pressure (bar)50 Speed (rpm) 15 (*) from upstream to downstream of the extruder.

On exiting the extruders, the three extruded layers were taken up by athree-roll polishing stack brought to a temperature of 70° C. It wasdifficult to delaminate the film obtained into its constituent layers,which attests to the adhesive properties of the central layer.

EXAMPLE 3R

This example is given by way of comparison.

Example 1 was reproduced except that the blend of the three constituents(A), (B), (C) was replaced by the constituent (A) alone in order tomanufacture the central layer of the coextruded film. The operatingconditions of the coextrusion and of the calendering were those fromExample 2. No adhesion was observed between the constituent layers ofthe film.

EXAMPLE 4R

This example is given by way of comparison.

Example 1 was reproduced except that the blend of the three constituents(A), (B), (C) was replaced by a copolymer of propylene grafted by methylmethacrylate in order to manufacture the central layer of the coextrudedfilm.

The operating conditions of the coextrusion are mentioned in Table 3below.

TABLE 3 Single-screw extruder 1 Extrusion of the lower layer (screwdiameter: 20 mm) (average thickness: 70 μm) Barrel temperature (° C.)(*) 180-210-210 Pressure (bar) 138 Speed (rpm) 40 Single-screw extruder2 Extrusion of the central layer (screw diameter: 20 mm) (averagethickness: 35 μm) Barrel temperature (° C.) (*) 160-175-175 Pressure(bar) 98 Material temperature 159 Speed (rpm) 60 Single-screw extruder 3Extrusion of the lower layer (screw diameter: 20 mm) (average thickness:200 μm) Barrel temperature (° C.) (*) 190-200-200-200 Pressure (bar) 95Speed (rpm) 15 (*) from upstream to downstream of the extruder.

The operating conditions of the calendering were those mentioned inExamples 1 and 2.

No adhesion was observed between the constituent lavers of the film.Furthermore, it was observed that the multilayer structure had anunpleasant odour.

1. A polymer composition with adhesive properties comprising: (1) atleast one fluoropolymer (A) grafted by at least one compound (a)containing at least one functional group (f1) capable of conferringadhesion properties on said polymer; (2) at least one polyolefin (B)grafted by at most 4% by weight, relative to the weight of polyolefin(B), of at least one compound (b) containing at least one functionalgroup (f2) chosen from acid and anhydride groups, optionally completelyor partially neutralized by at least one neutralizing agent; and (3) atleast one olefin copolymer (C), for which at least 5% by weight of therepeat units are derived from at least one functional monomer (f3)capable of reacting with the functional group (f1) contained in thecompound (a).
 2. The polymer composition according to claim 1, whereinsaid fluoropolymer (A) is a vinylidene fluoride polymer.
 3. The polymercomposition according to claim 1, wherein said functional group (f1) isselected from the group consisting of epoxy groups, alcohol groups, andcarbonyl groups.
 4. The polymer composition according to claim 1,wherein said compound (a) is selected from the group consisting of allylglycidyl ether, 3-allyloxy-1,2-propanediol, N-vinylpyrrolidone, andN-vinylcaprolactam.
 5. The polymer composition according to claim 1,wherein said polyolefin (B) is selected from the group consisting ofhomopolymers and copolymers derived from ethylene and propylene.
 6. Thepolymer composition according to claim 1, wherein said olefin copolymer(C) is a copolymer for which from 95 to 85% by weight of the repeatunits are derived from ethylene and for which from 5 to 15% by weight ofthe repeat units are derived from methacrylic acid, the acid functionsof which are completely or partially neutralized by the sodium ion. 7.The polymer composition according to claim 1, wherein the weight ratioof the fluoropolymer (A) to the polyolefin (B) is between 95/5 and 5/95.8. The polymer composition according to claim 1, wherein said olefincopolymer (C) is present in an amount of 0.1 to 10% by weight relativeto the total weight of said composition.
 9. The polymer compositionaccording to claim 1, wherein one portion of the amount of saidfunctional monomer (f3) has reacted with one portion of the amount ofsaid functional group (f1), thus chemically bonding said olefincopolymer (C) to said fluoropolymer (A).
 10. The polymer compositionaccording to claim 9, wherein one portion of the amount of saidfunctional monomer (f3) has reacted and/or developed ionic interactionswith one portion of the amount of said functional group (f2), thusbonding said olefin copolymer (C) to said polyolefin (B).
 11. Thepolymer composition according to claim 9, wherein one portion of theamount of said functional group (f2) has reacted with one portion of theamount of said functional group (f1), thus chemically bonding saidpolyolefin (B) to said fluoropolymer (A).
 12. The polymer compositionaccording to claim 1, wherein the entire amount of said functional group(f1), the entire amount of the said functional group (f2) and the entireamount of said functional monomer (f3) are in an unreacted state.
 13. Amethod for manufacturing the composition according to claim 1, accordingto which said fluoropolymer (A), said polyolefin (B) and said olefincopolymer (C) are mixed as a molten mass.
 14. A method for manufacturingthe composition according to claim 1, according to which saidfluoropolymer (A), said polyolefin (B) and said olefin copolymer (C) aremixed and reacted as a molten mass.
 15. A multilayer structure having anX/Y/Z configuration of layers X, Y and Z, wherein the central layer Y iscomposed of a polymer composition according to claim 1, wherein thelayer X is composed of a polyolefin, and wherein the layer Z is composedof a fluoropolymer.
 16. The multilayer structure according to claim 15,being manufactured in a final form of hollow bodies selected from thegroup consisting of tanks, bottles, containers, tubes, and pipes, thelayer X constituting the outer layer of said hollow bodies and the layerZ constituting the inner layer of said hollow bodies.
 17. A method ofuse of the multilayer structures according to claim 16 for the transportand/or storage of liquid hydrocarbons.